Tuesday, July 05, 2005

Specialized Neurons of the Medial Temporal Lobe

This study has been reported in the media in a number of different locations. Today, The New York Times includes a small report about it:
A Neuron With Halle Berry's Name on It
The New York Times
Published: July 5, 2005

Scientists have long wondered whether the brain contains "grandmother" cells - one or a few neurons that fire in response to the familiar face of your grandmother. A new study suggests that the answer may be yes.

And it is not just Grandma.

If you are a Halle Berry fan, you have a Halle Berry cell or two in your brain. Not a region, but a single cell or a small handful that fire in response to her face in various angles and poses, her body in a cat suit, the string of letters in her name and other distinct features of the actress who plays Cat Woman.

Dr. Christof Koch, a neuroscientist at the California Institute of Technology who helped conduct the study, said some neuroscientists had long argued for specialized neurons.

Others have said the brain does not have enough neurons to be that specialized, Dr. Koch said.

[ ... Read the full article ... ]

Here is the abstract of the study, published in the journal Nature:

Quiroga RQ, Reddy L, Kreiman G, Koch C, &Fried I. Invariant visual representation by single neurons in the human brain. Nature. 2005 Jun 23; 435(7045): 1102-1107.

Computation and Neural Systems, California Institute of Technology, Pasadena, California 91125, USA.

It takes a fraction of a second to recognize a person or an object even when seen under strikingly different conditions. How such a robust, high-level representation is achieved by neurons in the human brain is still unclear. In monkeys, neurons in the upper stages of the ventral visual pathway respond to complex images such as faces and objects and show some degree of invariance to metric properties such as the stimulus size, position and viewing angle. We have previously shown that neurons in the human medial temporal lobe (MTL) fire selectively to images of faces, animals, objects or scenes. Here we report on a remarkable subset of MTL neurons that are selectively activated by strikingly different pictures of given individuals, landmarks or objects and in some cases even by letter strings with their names. These results suggest an invariant, sparse and explicit code, which might be important in the transformation of complex visual percepts into long-term and more abstract memories.

PMID: 15973409 [PubMed - in process]
Anthony H. Risser | | |

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